• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.226-233
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• 2017

Jeung-pyun, a fermented rice cake, is prepared by fermenting rice sourdough using makgeolli, a traditional Korean rice wine, in the presence of yeast and lactic acid bacteria (LAB). The goal of this study was to conduct biochemical and microbial analyses of five different rice sourdoughs, each fermented with a different commercial makgeolli, using culture-dependent and culture-independent approaches. All sourdough samples fermented with different makgeolli for 6.5 h showed different profiles in pH, total titratable acidity, organic acid concentration, and microbial growth. LAB belonging to different genera were identified based on colony morphology on modified MRS and sourdough bacteria agar medium. PCR-denaturing gradient gel electrophoresis analyses of the five sourdoughs showed different bands corresponding to LAB and yeast. 16S/26S rRNA gene sequence analyses of the samples confirmed that the predominant LAB in the five fermented rice doughs was Lactobacillus plantarum, Lb. pentosus, and Lb. brevis. Various other Lactobacillus spp. and Saccharomyces cerevisiae were common in all five fermented samples. This study provides comprehensive and comparative information on the microflora involved in fermentation of rice sourdough and signifies the need to develop effective starters to enrich the quality of jeung-pyun.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.733-741
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• 2005

Waxy barley flour was fermented by two kinds of starter cultures; L. plantarum and L. brevis, alone or in combination and the effect was evaluated on waxy barley and wheat composite bread quality. In all three barley sourdoughs, fermentation decreased the pH, total sugar and reducing sugar, and increased lactic acid bacteria cell numbers. However yeasts (S. cerevisiae) were reduced. There was significant difference in physicochemical characteristics between the reference(composite barley dough containing improvement agent) and the barley sourdoughs (p <0.05). Barley sourdough fermented by L. plantarum showed more desirable farinogram properties of peak time, stability and elasticity than that of the reference. The rheofermentometer data for L. brevis produced the most $CO_2$ release curve, whereas L. plantarum held maximum $CO_2$ retention differed significantly from that of the breads made with barley sourdoughs fermented with the respectives starter cultures (p < 0.05). Barley sourdough bread fermented with L. plantarum resulted in better bread quality than the reference bread. The positive effect of fermentation with L. plantarum on bread quality was evident when comparing the well developed protein-starch matrix structure of the bread baked with barley sourdough with the reference bread.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.501-509
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• 2021

The increasing demand for baked products has given a boost to research on isolation and selection of novel yeast strains with improved leavening activity. Twelve sourdough samples were collected from several localities of the Fez region in Morocco. The pH and total titratable acidity (TTA) values of these samples varied from 3.03-4.63 and 14-17.5 ml of 0.1 N NaOH/10 g of sourdough, respectively, while yeast counts ranged from 5.3 6.77 Log CFU/g. Thirty-two yeast isolates were obtained and evaluated for their leavening ability. Out of all isolates, four yeasts molecularly identified as Saccharomyces cerevisiae (three strains) and Kluyveromyces marxianus (one strain) showed highest specific volumes of 4.69, 4.55, 4.35 and 4.1 cm³/g, respectively. These strains were further assessed for their tolerance to high concentrations of salt, sugar, elevated temperatures, and low pH conditions. K. marxianus showed higher resistance than the S. cerevisiae. Thus, Moroccan sourdoughs harbor technologically relevant yeasts that could be used as potential starters for bread preparation.

• The Korean Journal of Food And Nutrition
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• v.26 no.2
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• pp.199-207
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• 2013

This study was performed to evaluate the quality characteristics of sourdough bread with addition of lactic acid bacteria (LAB) in the antibacterial activity. The starter cultures were used for sourdough bread to increase bread shelf-life: Lactobacillus fermentum, Lactobacillus paracasei KB28, and Pediococcus pentosaceus MJK7. The results showed that the viable counts of lactic acid bacteria were increased in 8.1~9.2 log $cfu/m{\ell}$, respectively. The pH of the three sourdoughs was lower than that of control. In the texture characteristics, hardness, gumminess, and chewiness were tended to increase on the sourdough bread. Among the three sourdough breads, bread volume and retrogradation of bread were not significantly different. According to the results from preservation period, the sourdough breads with addition of Lb. paracasei KB28, Ped. pentosaceus MJK7 were showed the appearance of mold and bacteria growth in 5~6 days, whereas the control were showed in 3 days. As a result, a sensory evaluation indicated the highest overall acceptance in order of Lb. fermentum, Lb. paracasei KB28, Ped. pentosaceus MJK7. Based on these results, Lb. paracasei KB28 can be applicable to improve the quality of sourdough bread.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.84-97
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• 2016

Isolates from Korean fermented soybean paste were identified as Enterococcus faecium SBP12, Pediococcus halophilus SBP20, Lactobacillus fermentum SBP33, Leuconostoc mesenteroides SBP37, Pediococcus pentosaceus SBP41, Lactobacillus brevis SBP49, Lactobacillus acidophilus SBP55, and Enterococcus faecalis SBP58 according to conventional morphological and biochemical characteristics, carbohydrate fermentation profiling, and 16S rRNA sequence comparison. Strain SBP20, SBP33, SBP49, and SBP55 showed very resistance to simulated gastric and intestinal juices with final populations exceeding 6 log CFU/ml, whereas cells of SBP12 and SBP58 after exposure to low pH were dramatically decreased within 2 h. Among 4 strains having good tolerance to gastrointestinal conditions, the high adhesive ability to HT-29 cells, antibiotic resistance, and antimicrobial activity against food-borne pathogens Bacillus cereus ATCC 11778 and Staphylococcus aureus ATCC 6538 were observed with SBP49 and SBP55, therefore, these two strains were confirmed as putative probiotic candidates. There was no significant difference between the sourdoughs fermented with SBP49 and SBP55 with respect to the values of pH, total titratable acidity, and viable cell count. During sourdough fermentation, SBP49 strain produced significantly greater amounts of lactic acid than SBP55 strain, which secreted large quantities of hydrogen peroxide. SBP49 and SBP55 strains producing the antimicrobial substances such as lactic acid, hydrogen peroxide, and bacteriocin effectively inhibited B. cereus and S. aureus inoculated in the sourdough.